An olefin polymer such as an ethylenic polymer is molded into a bottle, foam, sheet, film, oriented film, etc. by various molding methods such as blow molding, expansion molding and film molding, and applied to various uses such as food packaging materials.
The oriented film is often applied to uses such as a shrink packaging film and the ethylenic polymer to be applied hereto is required to have a polymer chain that is easily oriented by stretching for molding a film, in other words, to have a long characteristic relaxation time.
As such an ethylenic polymer, an ethylene-α-olefin copolymer having a flow activation energy of 50 kJ/mol or more and satisfying a specific relationship between the melt-flow rate and the melt viscosity at the shearing rate of 100 rad/sec and at 190° C. has been proposed (see, for example, Patent Document 1).